Just 12 acts are left on the NBC competition series, which will air its finale on Monday. In honor of the momentous occasion, the series showed fan favorites like Susan Boyle, Darci Lynne Farmer, Angelica Hale, Shin Lim, Deadly Games and more videos of their first auditions. Only ET has the exclusive clip.

"This was a moment when my life changed, because I became a contestant on the show," Kechi Okwuchi emotionally reveals while watching her audition. "I feel like it would just be amazing to win."

"When I stood on the Britain's Got Talent stage for the first time, that was the beginning of the rest of my life, really," Boyle says. "I do believe in miracles. I would love to win."

See more reactions in the video player above.

During a recent interview with ET, Farmer opened up about how "grateful" she was to re-enter the competition after receiving the Judges' Wildcard.

"It has been crazy [to compete against all these acts]," she said. "I mean, I have seen these talents from all over the world on TV, and it's great to see them. They've inspired me. It's just been amazing to meet them and compete against them."

"The stakes are higher now that it's like, the best of the best competing against each other," added Farmer, who won season 12 of AGT. "Stakes are way higher. The pressure is on and the competition is a lot tougher."

The season finale of America's Got Talent: The Champions airs Monday at 8 p.m. ET/PT on NBC. See more in the video below.